ADDITIONS TO THE LATE PALEOCENE MOLLUSCAN FAUNA FROM THE SANTA-MONICAMOUNTAINS, LOS-ANGELES-COUNTY, SOUTHERN CALIFORNIA

Several previously unreported shallow-marine, warm-water gastropods an d bivalves from the upper part of the Santa Susana Formation, east-cen tral Santa Monica Mountains, Los Angeles County, southern California, are described and discussed. The gastropods are Diodora sp. nov.? (Fis surellidae) and Terebralia susana sp. nov. (Potamididae). The bivalves are Solena (Eosolen) stantoni (Weaver, 1905) (Solenidae), Martesia sp . (Pholadidae), and Nototeredo(?) sp. (Teredinidae). These mollusks ar e of late Paleocene (Thanetian Stage) age. For the Pacific Coast of No rth America, the specimens of Diodora and Martesia represent the earli est records, the specimens of Terebralia the first confirmed record, a nd the specimens of Nototeredo(?) the first record. The specimens of S olena (Eosolen) stantoni are the best preserved and largest of this sp ecies.